Oil burner



Sept 24, 1935. F. SPEAR I 2,015,572

' OIL BURNER Filed July 2, 1952 //V5 (ILA T/UN INVENTOR LEOLY/V F. SPEA K A TTORNEY PQtOIItCJQ SGPt. 24, l 935 UNITED .sTaTEs OFFICE on. BURNER i Leolyn r. Spear, Westiicld, Mm, minorto Gilbert & Barker Man West Springfield, sachuse'tts acturing Company,

Man, a corporation of Mas- Ap'plication July 2, 1932, Serial No. 620,640

. 2 Claims. (01. 15876) vThis invention relates to improvements in oil The invention will be disclosed for illustrative burners and has to do more particularly with the mounting of the nozzle, through which oil is emitted, and with the construction and arrangement of the oil supply conduit for said. nozzle.

. The invention is especially useful in connection with the so-called gun type burners,'wherein oil is forced under relatively heavy pressure toa nozzle of the mechanical or pressure atomizingtype and emitted, througha small orifice in said nozzle, in the form of a conical spray. It is very important and desirable to provide for a turbulent-flow of the oil'to the nozzle because there is produced by such flow a scrubbing action on the wall of the oil conduit which sweeps said wall free of bubbles of air or gas as wellas particles of solid matter. The tendency is to prevent accumulation of air or gas and solids and clogging of the conduit nozzle. It is also desired to have the oil conductor, or at least that part of it which lies immediately adjacent the nozzle, constructed with a very thick wall to afford amass of metal for rapidly conducting heat away from the nozzle and thereby aiding in preventing the latter from overheating. To secure the turbulence, a passage of very small caliber is necessary and this has to be provided in a member of much greater diameter, in order to secure the last-named advantage. The practical limitations of the extrusion process are such as to preclude the formation of such a member with a bore of the desired small diameter. Special and expensive operations would be necessary to form the small hole in said member and, if formed, it could not readily be cleaned.

This invention is directed to and has for its object the solution of the aforesaid problem. More particularly, the invention provides an oil conductor which hasthe desired large cross section and a bore therethrou gh of such size that the conductor can be simply and inexpensively produced, as by extrusion. With this conductor there is provided a rod of a diameter and length such as to fit in and fillthe bore in the conductor. This rod is mounted for convenient removal and replacementin said bore and the desired very small oilfeed channel is formedby grooving the ,outer surface of the; rod. The channel may bev easily cleaned by removing the rod. Also, whenever it is necessary to change the size of the channeLtherod may be removed and replaced by another one which has a channel of the desired size.

Other objects will appear as the detailed deappended claims.

plan view of Referring to the drawingfl the nozzle end only 10.

of the burner, is shown and the mechanism for forcing air and oil to the burner has been omitted as unnecessary to an understanding of the invention. Any mechanism, suitable for the purpose,

may be used and an example of onesuitable 1 mechanism will be found in U. S. Patent No. 1,832,131, granted November 17, 1931, to Hanni bal A. Kunitz. The burner disclosed herein isof the general type shown in the Kunitz patent but modified in accordance with the invention 20 disclosed in my U. S; Letters Patent No. 1,906,343, dated May 2, 1933.

In this burner, air at-low pressure is forced into a cylindrical tube 5, flowing from left to right as viewed in Figs. 1 and 2, and emerges 25 through upper and lower specially-formed'openings 8 (Fig. 2) in a head I, which closes the right hand end of the tube except for'the aforesaid air openings and others to be later described. This head I is fixed to two rods 9 (Fig. 1) which 30 extend rearwardly within tube 5 and are secured,

- as indicated, near their inner ends to a bracket 9 l5 (Fig. 3) within a circular opening IS in the bracket 9 and its position'in such opening may be varied, as desired, by adjustment of the set screws. The bracket 9 also serves to'support the insulating tubes II which carry the spark elec- 45v trodes [8 of the burner ignition means. The tube 5 has an opening l9 therein, normally closed by a semi-cylindrical cover 20. The arrangement is such that, by' removing this cover and bolt ID, the bracket 9 and with it the head-fl, nozzle i2 and spark electrodes may be drawn rearwardly and removed through opening i9,- the wires (not shown) to' the electrodes: l8 having' first been removed 'and the connection of ,pipe H tosupport I3 broken at the coupling I4.

By preference, the noule I2 is supported from head I through the intermediary of a shield member 2 I, rather than directly therefrom; The

objects are to substantially reduce the heat transferred by conduction from. head 'I to the. nozzle i 2 and its support I! and to allow airto pass around the nozzle for cooling and other purposes, as set forth in my prior patent. The shield proper is conical and is hollowed out to receive the nozzle i2 and the adjacent cylindrical portion 22 of support l3. Such portion 22 is engaged by four fins or ridges 23 on the interior of shield 2|,

which ridges support the portion 22 and nozzle l2 in spaced concentrical relation with the shield, as shown in Fig. 4, so that air can flow around the parts 22 and I2 and issue in a circular stream at the small open end of shield 2|. The portion 22 does not fit tightly within the four fins 23 and there is play enough to enable the support l8 to be moved to various positions within opening I! by the set screws l5. It will be seen, however, that there is but a small area of contact between the shield 2| and the portion 22. Similarly, there is but a small area of contact between the shield and head 1. The shield has integrally-formed, upper and lower skeleton arms 24 which contact with the head only at one point such as 25. The lower arm2l has an ear 26 which serves as a means of securing the shield in place, a screw 21 being passed through this car and threaded into head I.

As shown herein, air can flow through and around these skeleton arms 24 and some air can emerge between the body of the shield and head I, as by opening 21' (Fig. 4). subject matter of my prior patent and is not necessarily essential to the present invention. It is, however, desirable because of the material reduction in the amount of heat transferred by conduction from the head I to the nozzle l2 and its support l3 and also provides for some cooling of these parts.

The present invention has to do more particularly with the nozzle support I! and it is not limited to the one type of burner herein disclosed but has application generally to all burners of the gun type. According to the invention, this nozzle support is made of a metal having high.

heat conductivity, such as brassandit has a relatively large cross sectional area as compared to nozzle 12. The nozzle-supporting body is thus made efiective for conducting heat away from the nozzle very rapidly and it also presents a large surface area which is exposed to the air flowing through tube 5, whereby the heat conducted back from the nozzle l2 to support I8 is rapidly dissipated. The provisions disclosed in my prior patent serve to materially reduce the heating of the nozzle, by shielding it to some extent'from the reflected heat of the furnace and by spacing it from the head 1 to reduce the transfer of heat by conduction and to secure air fiow around the nozzle for cooling purposes. The present invention provides a large'mass of good heat conducting material in the .form of a nozzle support which rapidly conducts the heat away from the nozzle and aids materially in keeping the nozzle relatively cool.

It is most important to keep the nozzle cool. If it is allowed to get hot, the heat will crack the oil within the nozzle and a residue will be deposited therein. It is almost vital to keep the nozzle cool if carbon deposits thereon are to be avoided. Also, if the nozzle is hot, the oil in it expands after the burner stops and drips over the external face thereof. There is at that time,

This shield forms they no means available to atomize such .oil as drips from the nozzle, and accordingly it carbonizes. D'eposited carbon acts like a wick and absorbs more oil which carbonizes and adds to the trouble.

The blackened nozzle becomes even hotter because the rough black surface absorbs more heat rays than a bright polished surface. The action continues and eventually a heavy layer of carbon is formed. Oil absorbed by such layer burns like a smoky torch after the burner has stopped still further heating the nozzle and making the conditions worse.

It will be appreciated that the likelihood of troubles, such as have been just described,- can be still further reduced by reducing the volume of oil in the parts which are subjected to high temperature. That is, the smaller the volume of oil, subject to expansion by the heat of the. surrounding parts, the smaller will be the drip from the nozzle. While a heat conductor such as I3 has the advantage of carrying heat away from the nozzle, it ordinarily has the disadvantage of containing a considerable volume of oil which will, of course, be expanded by the heat of the member II. To overcome this disadvantage, a very small oil passage is provided in the member l3. As shown, the oil passage is a groove 28 formed in the periphery of a rod 29 which is inserte'd in and fills a hole in support Hi. The rod closely flts the hole in support l3 with only enough 30 clearance to enable the rod to he slid into and out of its position inthe support.

The particular way in which the oil channel of very small cross sectional area is provided is thought important. It would be very diflicult to form a hole, as small in area as channel 28, through the long support I3 by usual manufacturlng methods, such for example as extrusion. Manufacture by other methods would be difficult and the cost excessive. Also, allowing that it was feasible to form through the long member l3 a hole of such small diameter, it would be exceedingly difiicult to clean it as may be necessary from time to time. The present construction is one that lends itself readily to manufacture at low cost and enables easy cleaning of the small oil passage. The groove 28 is easily formed in rod 29 and the large hole in support l3 can readily be formed by the extrusion process. Then, when rod 29 is slid into the hole in the support, I 3, such hole is closed off except for the desired small channel 28. Whenever cleaning of the channel is necessary, the rod 29 is easily removed, after nozzle l2 has been unscrewed.

It will be appreciated that the construction of the oil channel in a rod, which can be easily removed from and replaced in the bore of the oil conductor l3, has another advantage in that it enables variation in size of the channel to be easily efiected. If larger or smaller channels are desired, the rod 29 can be removed and replaced by other rods of the same diameter but having channels of different size.

The small oil feed channel is also desirable in that it causes a turbulent flow of oil to the nozzle. Turbulent flow results when the channel is small enough to produce a noticeable drop in pressure between the inlet and the-outlet. Such is the case here. A turbulent flow to the nozzle is very desirable in that it tends to prevent the nozzle from becoming clogged. Any particles of solid matter carried along with the oil are kept in motion and stirred up so that they do not settle down and accumulate in a large mass to clog the nozzle. These small particles will come through the nozzle one by one instead of in a group which would be liable to stop the flow through the nozzle orifice.

It will be noted that the nozzle support I! slopes The nozzle-is rearwardly as does the oil pipe I I. thus located at the high point in the oil line, which is very desirable as enabling all air and gas to be readily driven out of the nozzle. There is often present in the oil some dissolved air and gas. Occasionally also, some air may leak into the oil line. Thus bubbles'of air or gas from either of these sources may be present in the oil pumped to the nozzle. It is important to avoid any condition in the nature of a trap where air and gas may accumulate, and the upward slant of the oil line toward its outlet at nozzle l2 avoids such a condition.

It is to be noted that the use of a single, very small oil channel which serves as the terminal portion of the oil supply pipe and is of capillary proportions relatively to the main portion of said pipe, aids materially in overcoming the trouble due to air and gas. In the first place, there is little room in which air and gas can accumulate.

' Second, the turbulent flow produced in channel 28 causes a scrubbing action on the walls of the channel 28, which prevents air and gas from accumulating thereon.

What I claim is:

1. In an oil burner, a tube through which air to support combustion is supplied, a valveless pressure-atomizing nozzle positioned adjacent the outlet end of said tube for spraying oil to be mixed with the air, the outlet end of the tube and nozzle being exposed to the heat of the combustion chamber and subjected to heat reflected back therefrom for an interval after the burner stops, and means for rapidly conducting heat away from the nozzle and dissipating it by radiation to the surrounding air in said tube, said means compris ing a member supporting at one end the nozzle and extending rearwardly in said tube for a substantial distance exposed to the air in said tube, said member having relatively high heat conductivity and relatively larg cross sectional area to effectively corgiWeat and a relatively large surface are e ed to the air in said tube,

an oil supply conduit connected to said member near its rearward end, said member having a single, very small oil feed channel of capillary proportions relativelyto said conduit for interconnecting said conduit and nozzle and for minimizing the volume of residual oil present in the heat conducting member when the burner is shut 5 oil, the heat conducting and heat radiating characteristics of said member being such as to prevent substantial expansion of said residual oil.

2. In an oil burner, a tube through which air to support combustion is supplied,- a valveless pressure-atomizing nozzle positioned adjacent the outlet end of said tube for spraying oil to be mixed with the air, the outlet end of the tube and nozzle being exposed to the heat of the combustion chamber and subjected to heat reflected back therefrom for an interval after the burner stops, and means for rapidly conducting heat away from the nozzle and dissipating it by radiation to the surrounding air in said tube, said means comprising a member supporting at one end the nozzle and extending rearwardly in said tube for a distance mam! times greater than the length of the nozzle and exposed to the air in said tube, said member having a cross sectional area larger than that of said nozzle and made of material having high heat conductivity for the purpose of rapidly conducting heat away from the nozzle and having also relatively large surface area exposed to said air for the purpose of dissipating the heat by radiation, said member having an oil inlet at a point remote from said nozzle and a long bore extending from said inlet to said nozzle and of a cross sectional area comparable to that of said inlet, and a rod having in its outer surface a single longitudinal groove of verysmall cross sectional 85 area of the order of no more than one one-hundredth of the cross sectional area of said member, said rod removably mounted in said bore and extending from end to end thereof closely fitting the wall thereof and filling the bore except for said groove, the latter affording an oil feed channel between said inlet and nozzle of sufliciently small area to secure high velocity and turbulent flow to produce a scrubbing eifect' on the wall of said channel, said rod being removable from said bore when the nozzle is detached to enable said channel to be easily cleaned.

LEOLYN F. SPEAR. 

